Created attachment 632276 [details] [diff] [review]
update and optimize Arabic char processing in TransformText
nsTextFrameUtils::TransformText is responsible for detecting Arabic characters, in order to support the bidi.numeral processing within textruns. However, the macros it uses to identify Arabic characters are out of date with respect to Unicode (they don't account for the Arabic Supplement and Extension blocks). They can also be rewritten slightly to run more efficiently, which is important because TransformText is showing up as a significant contributor to profiles in bug 762710, for example.
The attached patch updates the Arabic character range, and by optimizing the order of comparisons, it also shaves around 5-10ms off the reflow time for the tinderbox log in bug 762710#c0 (on my MBP).